The wonderful gold standard

"Some scholars have theorized that the images and characters used by Baum and Denslow closely resembled political images that were well known in the 1890s, specifically the debate of the day regarding monetary policy: the "Yellow Brick Road" represents the gold standard, the silver slippers (which were ruby slippers in the film version) represent the sixteen to one silver ratio (dancing down the road). (...) The wicked witches of the east and west represented the local banks and the railroad industry, respectively, both of which drove small farmers out of business. The scarecrow represents the farmers of the Populist party, who managed to get out of debt by making more silver coinage. The return to bimetalism would increase inflation, thus lowering the real value of their debts. The Tin Woodman represents the factory workers of the industrialized North, whom the Populists saw as being so hard-pressed to work grueling hours for little money that the workers had lost their human hearts and become mechanized themselves. Toto was thought to be short for teetotaler (...) It has also been suggested the cowardly Lion represented Wall Street investors, given the economic climate of the time. The Munchkins represented the common people (serfdom), while the emerald city represented Washington and its green-paper money delusion. The Wizard, a charlatan who tricks people into believing he wields immense power, would represent the President. (...) Moreover, "Oz" is the abbreviation for the measuring of these precious metals: ounces."

Sources: Wikipedia and Principles of Economics, de G.Mankiw